* {
    font-family: "Arial","Microsoft YaHei","黑体","宋体",sans-serif;
}

html {
    overflow: auto;
    overflow-x: hidden;
    scroll-behavior: smooth;
}

#main-page {
    width: 100%;
    height: 100%;
    position: absolute;
}

#header {
    width: 100%;
    height: 10%;
    position: fixed;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 999;
}

#logo-holder {
    width: 5%;
    height: 100%;
    position: absolute;
    left: 0px;
    display: flex;
    align-items: center;
    justify-content: center;
    align-content: center;
}

#logo {
    position: absolute;
    width: 50%;
    height: 50%;
}

#menus-list {
    width: 95%;
    height: 100%;
    position: absolute;
    right: 0px;
    display: flex;
    align-items: center;
    align-content: center;
    justify-content: center;
}

#header-wrapper {
    display: flex;
}

ul {
    list-style: none;
    display: block;
    position: absolute;
    height: 100%;
    width: 100%;
}

li {
    padding: 10px;
    text-align: center;
    align-items: center;
    justify-content: center;
    display: flex;
}

a {
    color: white;
    font-size: 20px;
    text-decoration: none;
}

a:hover {
    border-bottom: 2px solid white;
}

#right-menus {
    position: absolute;
    height: 100%;
    width: 20%;
    right: 0;
    align-items: center;
    justify-content: center;
    align-content: center;
    display: flex;
}

body {
    position: absolute;
    height: 100%;
    width: 100%;
    background-size: cover;
    background-image: url("background1.jpg");
    background-repeat: no-repeat;
    display: block;
}

#middle-content {
    position: absolute;
    width: 80%;
    height: 20%;
    top: 45%;
    left: 20%;
    display: flex;
}

#left-description {
    position: absolute;
    height: 100%;
    width: 40%;
    display: flex;
    flex-direction: column;
}

#titles {
    display: flex;
    flex-direction: column;
}

#big-title {
    height: 200px;
    display: flex;
    color: whitesmoke;
}

#subtitle {
    height: 120px;
}

#big-title h1 {
    font-size: 100px;
}

h4 {
    font-size: 30px;
    color: white;
}

#about-page {
    height: 100%;
    width: 100%;
    position: relative;
    top: 100%;
    background: #03A9F4;
}

#contact-page {
    height: 100%;
    width: 100%;
    position: relative;
    top: 100%;
    background: chartreuse;
}